IAC and other misc problems 1.8 swap, using 90-93 megasquirt PNP
 

i just put a 96 motor in my 1990 miata, i have a flyin Miata turbo kit and im running it with a 90-93 megasquirt. It starts and roughtly idles, but far from complete.

my problem is that when idling, there is a small buzzing sound from the IAV. What does a bad IAV sound like?
I modified the ECU TPS sensor, and calibrated it from 112-212. Can anyone comfrim that is correct.
https://www.miataturbo.net/megasquirt-18/how-wire-analog-tps-ms-90-93-car-36271/

Also, what setting do i need to change going from 1.6 to 1.8?


Can anyone post a base tune for a 1.8 turbo miata with megasquirt?

anyone have some idea's ?

I swapped a 96 engine into my 91 running on a DIY MS1 and had a similar issue. The frequency settings for the 1.8 and 1.6 IACs are different. I don't remember what I ended up using, but if you play around with the frequency and duty cycle settings you can get it in a range that stops the buzzing. Do a search on here for the settings that are usually used on the 1.8s. You are running the 1.8 TB right? If you swapped the 1.6 TB, I don't have any idea what it could be.

The 1.8 IAC valve idles at about 300-400 Hz with the stock ECU. Rises and falls with rpm.